Thrust bearings are a type of bearing which support an axial load while permitting rotation of a shaft, for example, a rotary shaft of a pump. Fluid film thrust bearings typically comprise a circumferential array of pads that support the thrust load through hydrodynamic fluid films between the individual pads and the rotating thrust runner. Supporting the pads, there is usually a load-equalizing linkage mechanism having pivotally-connected overlapping links that keep the loads nearly uniform among the pads. In double-acting thrust bearings, having two sets of pads on opposite sides of the runner to accommodate thrust load reversals, there is often an elastic preloading mechanism within the load-equalizing linkage to maintain some nominal loading in the inactive (non-loaded) side. Typical preload mechanisms include coil springs, wave washers or elastomeric o-rings.
A need, however, exists for an improved preload assembly.